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Re: 12 GPU Limit
Posted: Wed Jun 17, 2015 1:59 pm
by smicha
electric_eric wrote:
Hey,
I currently have 8 x 980ti recognised in device manager however only 7 cards show up in Octane or Geforce Experience.
I have the same motherboard as you and I'm running windows 8.1 64bit.
Did you have to disable much in the bios to get these 9 cards working?
Any help on this would be much appreciated as I currently have a 980ti sat on the table doing nothing!!
Thanks in advance.
Your i2500k has 16 pci-e lanes, not 40 as 4930k. So this may be the reason why you cannot get 8 gpus working. But this is just a hint, not sure about it. We've written about it a lot at Tutor's topics.
Re: 12 GPU Limit
Posted: Wed Jun 17, 2015 2:36 pm
by electric_eric
I should mention this is a different PC I'm talking about so ignore my profile spec.
In the system I'm talking about we have a Intel Core i7 4820K Quad Core processor.
Cheers.
Re: 12 GPU Limit
Posted: Wed Jun 17, 2015 2:47 pm
by smicha
electric_eric wrote:I should mention this is a different PC I'm talking about so ignore my profile spec.
In the system I'm talking about we have a Intel Core i7 4820K Quad Core processor.
Cheers.
So again: 4820k had 28 pcie lanes and this would allow for only 7 gpus in x4 mode...
Re: 12 GPU Limit
Posted: Wed Jun 17, 2015 2:50 pm
by electric_eric
http://ark.intel.com/products/77781/Int ... o-3_90-GHz
If you look at the expansion options here it states that it has "Max # of PCI Express Lanes 40"
Re: 12 GPU Limit
Posted: Wed Jun 17, 2015 2:52 pm
by smicha
Oh, I thought that 4820 has same as 5820. So this must have something common with IO space.
Re: 12 GPU Limit
Posted: Wed Jun 17, 2015 3:01 pm
by electric_eric
IO space? What does that mean exactly?
The thing that's baffling me is that there are 8 GPU's in device manager all of which have "working properly" status, which suggests to me that they are installed correctly.
Not sure why all 8 wouldnt then show up in Octane device list.
Re: 12 GPU Limit
Posted: Wed Jun 17, 2015 3:38 pm
by electric_eric
Could it be a RAM issue?
We have 32GB of RAM installed for 8x 6GB cards. I've heard that recommended is 2-3 times the GPU memory but is that 'combined' memory?
Re: 12 GPU Limit
Posted: Wed Jun 17, 2015 5:35 pm
by smicha
In this topic
http://render.otoy.com/forum/viewtopic. ... ilit=tutor
you'll find very useful info. Tutor is a great helper, so I believe he'll give you some hints.
Re: 12 GPU Limit
Posted: Thu Jun 18, 2015 11:01 am
by electric_eric
Thanks, that's been a great help.
We now have 8 cards working
Now for number 9.
Re: 12 GPU Limit
Posted: Thu Jun 18, 2015 11:36 am
by smicha
electric_eric wrote:Thanks, that's been a great help.
We now have 8 cards working
Now for number 9.
Great news. What actually caused the problem?